Along with many others, I'd like the Biden administration to do more than they have to prevent further devastation. But let's not create a false equivalence between current policy and what Trump would be telling Israel. The Biden administration has reportedly told Israel to not assault Rafah, period. To some degree, you're right that the administration always feels a step behind, but they're stuck between a rock and a hard place. There is no policy we could choose that would appease both sides (and I don't mean Israel as one of those sides). We like to think POTUS is the most powerful person in the world, but is he really? Why can't he even get Bibi to stand down?
There just are no good solutions here, and I think what needs to be crystal clear to Israel is that there is a red line (i.e. full assault on Rafah), and if they cross it, there will be severe consequences (we pull the plug on military aid). Otherwise we're a dog that's all bark, and no bite. (To state the obvious, I don't think we're anywhere near abandoning Israel as a staunch ally, for reasons that do include pro-Israel lobbying.)
If Trump was POTUS, he would have green-lit a ground invasion of Rafah over a month ago. How do you even know that 50k deaths are inevitable any way you slice it, so it's politically preferable to get it over with quickly? For one, I think the Biden administration is trying to prevent 50k more deaths. And two, I think assaulting Rafah would open the door to Hezbollah and Iran escalating, and now you have a much more dangerous regional war that almost certainly draws in U.S. armed forces.
I don't think Gaza will be a top-4 issue for voters in November (1 and 2 are clearly the economy and the southern border). It could be important in Michigan*, but "It's the economy, stupid" will most likely be decisive across the handful of battleground states. IMHO people's
feelings about the economy will be baked in sometime this summer, and are unlikely to change a month or two before the election.
* Very sobering article centered around Dearborn:
Michigan has the power to unravel a second Biden presidency. It just might.
slate.com